If anyone advertises P2P when it's not, it should be illegal. I have no idea what type of P2P you are talking about but most of the centralized exchanges I know does a P2P keeping itself as a escrow system. Having a escrow in P2P don't make than non-P2P.
P2P meaning already expand just like staking which is originally to pledge your token to help for blockchain delegation which is now also use on DeFi as staking meaning holding your tokens on a smart contract address in exchange for profit yield.
The currency P2P that being use by the exchange is what many average joe crypto people understand its meaning and not the real peer to peer network like the Bitcoin transactions. Exchange use P2P concept because trader directly trade to each other without interference of exchange. This is the centralized P2P like staking on DeFi. We can't control what will be the definition of a P2P because there's no copyright on this word.